The inventive concept relates generally to touch panels. More particularly, certain embodiments of the inventive concept relate to capacitive touch panels having electrodes with perforations.
A touch panel is an input device configured to sense a touch input. For instance, it may sense a user's finger or a stylus at or near a surface of the touch panel. In one common implementation, a touch panel is disposed on a front side of an image display device. Where an input tool is placed in contact with a screen of the touch panel, the touch panel coverts a contact position into an electrical signal. A touch panel can be implemented with any of several different techniques or technologies, such as a resistive overlay technique, a capacitive overlay technique, a surface acoustic wave technique, or an infrared method technique. Additionally, a touch panel can be implemented with multi-touch capability, e.g., using the capacitive overlay technique.
A touch panel implemented with the capacitive overlay technique can be referred to as a capacitive touch panel. A capacitive touch panel typically comprises multiple sensing electrodes. Where a finger or a touch pen comes in contact with the screen of the capacitive touch panel, the capacitive touch panel senses capacitance variation (or electric field variation) between the sensing electrodes and converts a contact position into an electrical signal.
In general, the performance of a capacitive touch panel can be evaluated according to touch sensitivity and touch accuracy. As touch sensitivity becomes higher, response time tends to increase. One way to increase touch sensitivity is by increasing a capacitance and a variation ratio of the capacitance between the sensing electrodes. Where the finger or the touch pen comes in contact with the screen, touch accuracy is defined as an error rate of a real touched position and a contact position calculated by a driving circuit. The touch accuracy may increase with improvements in uniformity of the capacitance variation (or the electric field variation) of a touch region. In view of these and other features of existing technologies, there is a general need for techniques capable of increasing the touch accuracy of capacitive touch panels.